With the development of communication technologies, the communication networks of different types coexist in a region. For example, FIG. 1 shows the coexistence of a wireless local area network (WLAN), a worldwide interoperability for microwave access (WiMAX) network, and a cellular network. In addition, multi-mode terminals that can communicate with different networks are developed accordingly. The service areas and service capabilities of different communication networks are different. Therefore, the key technology is to ensure that a mobile terminal can implement seamless handover between different media networks.
At present, the 802.21 protocol defines an architecture for implementing the media independent handover (MIH) service for multi-mode terminals, as shown in FIG. 2. In this architecture, an MIH layer is added between L2 (the link layer) and L3 (the network layer) in the protocol stack of a network entity. At the MIH layer, the interfaces with the upper layer of the protocol stack, the lower layer of the protocol stack, the network management system (NMS), and the media independent handover function (MIHF) entity at the peer end are defined to provide event, command, and information services for multi-mode terminals to implement seamless handover between different media networks.
When providing services for multi-mode terminals to implement seamless handover between different media networks, the upper layer/MIH users/NMS entity needs to query the bottom layer/link layer for parameters.
The conventional technology related to the present invention provides a method for querying parameter information. The query process is illustrated in FIG. 3 and described below:
The upper layer/MIH users/NMS entity sends an MIH_NMS_Get_State.request command to the MIH layer and specifies one or more parameters to be queried through the “StateInformationRequestList” which is a parameter list of state information requested. Table 1 defines the “StateInformationRequestList” parameter.
TABLE 1ValidNameTypeRangeDescriptionStateInformationResponseListListN/AList of the stateinformation
After receiving the MIH_NMS_Get_State.request command sent from the upper layer/MIH users/NMS entity and finding that certain link layer parameters need to be queried, the MIH layer uses a Link_Get_Parameters.request command to initiate a link parameter query request to the bottom layer/link layer and uses a list parameter “LinkParameterList” in the Link_Get_Parameters.request command to specify one or more link parameters to be queried at the link layer. Table 2 defines the “LinkParameterList” parameter.
TABLE 2ValidNameTypeRangeDescriptionLinkParameterListListN/AA list of link parameters
After receiving the link parameter query request sent from the MIH layer, the bottom layer/link layer acquires the current values of the link parameters to be queried, uses a Link_Get_Parameters.confirm command and the “LinkParameterList” parameter in the command to return the current values to the MIH layer, and uses an enumerated parameter “Status” in the Link_Get_Parameters.confirm command to return the status (“Success” or “Error”) of the result of querying link parameters to the MIH layer. Table 3 defines the “LinkParameterList” and “Status” parameters.
TABLE 3ValidNameTypeRangeDescriptionLinkParameterListListN/AA list of link parametersStatusEnumeratedSuccessStatus of operationError
After receiving the Link_Get_Parameters.confirm command sent from the link layer, the MIH layer parses the link parameter values from the “LinkParameterList” parameter in the command and returns the link parameter values to the NMS through an MIH_NMS_Get_State.confirm command and a “StateInformationResponseList” parameter in the command. Table 4 defines the “StateInformationResponseList” parameter.
TABLE 4ValidNameTypeRangeDescriptionStateInformationResponseListListN/AList of the stateinformation
The method in the conventional technology has the following defects:
1. In the conventional technology, the “LinkParameterList” parameter in Link_Get_Parameters.request and Link_Get_Parameters.confirm commands is uniformly defined as “a list of link parameters”. In addition, according to the current definition, the “LinkParameterList” parameter in the Link_Get_Parameters.request command is a parameter list that contains “RSSI”, “SNR”, “C/I”, “BER”, “PER”, and “Link Data Rate” elements and the “LinkParameterList” parameter in the Link_Get_Parameters.confirm command is a list that contains the values of the preceding parameters. In such a query mechanism, to query the bottom layer/link layer for parameters, the MIH layer needs to ensure that the order of the elements in the “LinkParameterList” parameter in the Link_Get_Parameters.request command is the same as that of the elements in the “LinkParameterList” parameter in the Link_Get_Parameters.confirm command and thus to ensure that the parameter values in the LinkParameterList parameter in the Link_Get_Parameters.confirm command correspond to the parameter names in the “LinkParameterList” parameter in the Link_Get_Parameters.request command. Otherwise, the correspondence between the returned parameter values in the Link_Get_Parameters.confirm command and the parameter names cannot be determined. Therefore, it is complex to implement the query mechanism in the prior art.
2. In the conventional technology, the “StateInformationRequestList” parameter in the MIH_NMS_Get_State.Request command and the “StateInformationResponseList” parameter in the MIH_NMS_Get_State.confirm command are both defined as “list of the state information”. In addition, according to the current definition, the “StateInformationRequestList” parameter in the MIH_NMS_Get_State.Request command is a list that contains state information and the “StateInformationResponseList” parameter in the MIH_NMS_Get_State.confirm command is a list that contains the corresponding state values. In such a query mechanism, to query the MIH layer for parameters, the upper layer/MIH users/NMS entity needs to ensure that the order of the elements in the “StateInformationRequestList” parameter in the MIH_NMS_Get_State.Request command is the same as that of the elements in the “StateInformationResponseList” parameter in the MIH_NMS_Get_State.confirm command and thus to ensure that the state values in the “StateInformationResponseList” parameter in the MIH_NMS_Get_State.confirm command correspond to the state names in the “StateInformationRequestList” parameter in the MIH_NMS_Get_State.Request command. Otherwise, the correspondence between the returned state values in the MIH_NMS_Get_State.confirm command and the state names cannot be determined. Therefore, it is complex to implement the query mechanism in the prior art.
3. In the conventional technology, the MIH_NMS_Get_State.confirm command does not contain a parameter such as “Status” used for the MIH layer to return the status of the query result to the upper layer/MIH users/NMS entity. As a result, the upper layer/MIH users/NMS entity does not know the status (“success” or “error”) of the result of state information query and thus fails to determine whether the returned state value is valid.